There are many usage models for Ultrasound Doppler technology such as the ability to find the location and velocity of a target object, monitoring a baby's heartbeat in utero, or measuring the thickness of an object. Devices capable of performing these usages are generally unique and focused on a specific application.
Smartphones and other similar mobile computing devices have become the predominant technological devices that people carry around with them to perform a wide variety of tasks, such as making phone calls, sending emails, taking pictures, and surfing the web while on the go. With each successive wave of mobile computing devices that are introduced, more functionality continues to be integrated to allow the smartphones/devices to perform an ever-increasing array of tasks.